Now his long interest in soil cuisine has finally culminatedin a feast he's been offering to customers the last few weeks,starting with an amuse bouche of soil soup and ending with asoil sorbet.

"Man didn't create the sea, the air or the soil. They'resimply all part of nature, and in a sense they are alive intheir own right," said Tanabe. "What I'm trying to do is reflectthat feeling in food."

A professional bantamweight boxer in his youth, Tanabeturned his hand to cooking in his twenties and left to train inFrance. For the last 20 years he has run a French restaurant indowntown Tokyo, and over the last eight has been slowlyintroducing his customers to samples of soil-inspired cuisine.

At first, though, the search for a clean and chemical-freemain ingredient was tough work.

"I had to go all over the place to find soil, into themountains and places like that. Places where there was nofarming," he said. "Then of course I had to dig it up from deepunder the ground."

Now Tanabe sources his soil through a Tokyo-based supplierwhich delivers about a kilo (2.2 lbs) of dirt a day, pre-checkedfor harmful substances. Previously, limited supplies had meanthe could only serve an occasional soil dish or two.

After the dirt arrives, he lightly cooks it to release theflavour, then runs it through a sieve to remove any stray grainsof sand.

The six-course soil extravaganza starts with an amuse boucheof soil soup, served with the merest fleck of dirt-engrainedtruffle, and ends with soil sorbet and a sweet dirt gratin.

But Tanabe's pride and joy is the "soil surprise," adirt-covered potato ball with a truffle centre.

The feast is not especially cheap, running to 10,000 yen($110) a diner.

Many are surprised by the unusual dining experience.

"It was my first time to have soup made from soil," saidHiromi Fujie, a nearby resident. "It was a bit gritty but not atall unpleasant, a little like vegetable soup. I liked it."

If Tanabe is to be believed, it's healthy too. He says hissoil aids the digestion and is full of healthy minerals.

"Humans used to eat soil, back in the day," he said, thoughhe had to ruefully acknowledge that not all customers are fans.

"Animals eat is as well, so I suppose there's thisimpression that soil's a bit too dirty to eat. We do have somecustomers who completely avoid it."($1 = 93.4300 Japanese yen)